Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Conference Object Citation - Scopus: 4Trans-resveratrol’ün Kitosan Mikroküreler İçerisindeki Kararlılığı(Institute of Electrical and Electronics Engineers Inc., 2009) Altıok, Duygu; Altıok, Evren; Bayraktar, Oğuz; Tıhmınlıoğlu, Fundatrans-Resveratrol, (3,5,4?-trihydroxy-trans-stilbene), a phenolic compound present in some plant species, have been shown to posses antioxidative, anticarcinogenic and antitumour properties. However, under UV light, it turns into -cis form and looses its bioactivity.This study aims to increase the stability of trans-resveratrol by loading it into chitosan microspheres. Within this context, the trans-resveratrol loaded chitosan microspheres was produced by spray drying and then the resultant microspheres were characterized. The particle size and the surface morphology of resultant microspheres were investigated by scanning electron microscope (SEM) and the thermal properties were determined by thermogravimetry analyser(TGA). The stability of free and that of inside the microspheres was determined by high performance liquid chromatography (HPLC). It was found that the stability of trans-resveratrol incorporated into chitosan microspheres kept constant. ©2009 IEEE.Article Citation - WoS: 25Citation - Scopus: 29Antibacterial Properties of Silk Fibroin/Chitosan Blend Films Loaded With Plant Extract(Korean Fiber Society, 2010) Başal, Güldemet; Altıok, Duygu; Bayraktar, OğuzThe silk fibroin (SF)/chitosan (CHI) blend films were prepared by dissolving them in formic acid. The morphology of the films was examined by scanning electron microscopy (SEM). The roughness of the membranes was determined by atomic force microscopy (AFM). These films were treated with the extracts of Pistacia terebinthus, Pistacia lentiscus, and Hypericum empetrifolium. Folin-Ciocalteu assay was used to determine the amount of total phenols adsorbed on these blend films. The antibacterial properties of films were tested using disc diffusion and turbidity measurement methods against Escherichia coli and Staphylococcus epidermidis. The release of adsorbed phenolics from the film surface resulted in antibacterial properties. © The Korean Fiber Society and Springer Netherlands 2010.Article Citation - WoS: 347Citation - Scopus: 397Physical, Antibacterial and Antioxidant Properties of Chitosan Films Incorporated With Thyme Oil for Potential Wound Healing Applications(Springer Verlag, 2010) Altıok, Duygu; Altıok, Evren; Tıhmınlıoğlu, FundaChitosan films incorporated with thyme oil for potential applications of wound dressing were successfully prepared by solvent casting method. The water vapor permeability, oxygen transmission rate, and mechanical properties of the films were determined. Surface and cross-section morphologies and the film thicknesses were determined by Scanning Electron Microscopy (SEM). Fourier transform infrared (FT-IR) spectroscopy was conducted to determine functional group interactions between the chitosan and thyme oil. Thermal behaviors of the films were analyzed by Thermal Gravimetry (TGA) and Differential Scanning Calorimetry (DSC). In addition, the antimicrobial and the antioxidant activities of the films were investigated. The antimicrobial test was carried by agar diffusion method and the growth inhibition effects of the films including different amount of thyme oil were tested on the gram negative microorganisms of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and a gram positive microorganism of Staphylococcus aureus. The minimum thyme oil concentration in chitosan films showing the antimicrobial activity on all microorganisms used in the study was found as 1.2 % (v/v). In addition, this concentration showed the highest antioxidant activity due to mainly the carvacrol in thyme oil. Water vapor permeability and oxygen transmission rate of the films slightly increased, however, mechanical properties decreased with thyme oil incorporation. The results revealed that the thyme oil has a good potential to be incorporated into chitosan to make antibacterial and permeable films for wound healing applications. © 2010 Springer Science+Business Media, LLC.Article Citation - WoS: 51Citation - Scopus: 55Kinetic Modelling of Lactic Acid Production From Whey by Lactobacillus Casei (nrrl B-441)(John Wiley and Sons Inc., 2006) Altıok, Duygu; Tokatlı, Figen; Harsa, Hayriye ŞebnemThe biomass growth, lactic acid production and lactose utilisation kinetics of lactic acid production from whey by Lactobacillus casei was studied. Batch fermentation experiments were performed at controlled pH and temperature with six different initial whey lactose concentrations (9-77 g dm-3) in a 3 dm3 working volume bioreactor. Biomass growth was well described by the logistic equation with a product inhibition term. In addition, biomass and product inhibition effects were defined with corresponding power terms, which enabled adjustment of the model for low- and high-substrate conditions. The Luedeking-Piret equation defined the product formation kinetics. Substrate consumption was explained by production rate and maintenance requirements. A maximum productivity of 2.5 g dm-3 h-1 was attained with an initial lactose concentration of 35.5 g dm-3.